Petrified Wood
Silicified Wood (SiO2)
Category
Browse organic (non geological) specimens identified by the Rock Identifier community.
Petrified Wood
Silicified Wood (SiO2)
Pyrite Concretion
Iron Sulfide (FeS2) in Sedimentary Matrix
Tiny metallic mineral fragment, possibly native gold
Native gold (Au), unconfirmed; could also be pyrite or chalcopyrite
Petrified Wood
Silicified Wood (primarily SiO2)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Man-made Crystal (Lead Glass)
Lead oxide-doped Silica Glass (approx. SiO2 + PbO)
Fulgarite
Fulgurite (Lechatelierite / Vitrified Sand)
Petrified Wood
Silicified Wood (SiO2)
Agatized Petrified Wood
Silicon Dioxide (SiO2) - Chalcedony pseudomorph after Wood
Gastropod Fossil (Snail Steinkern)
Class Gastropoda (internal mold)
Petrified Wood
Silicified Wood (SiO2)
Rainbow Obsidian
Volcanic glass (SiO2 - approximately 70% or more silicon dioxide)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Shale
Mudrock / Fissile Shale
Obsidian
Obsidian (Amorphous volcanic glass, SiO2 with impurities)
Bull Quartz
Quartz (Silicon Dioxide - SiO2)
Weathered sandstone cobble
Quartz-rich sandstone, primarily SiO₂ with clay/iron-oxide cement
White seed-bead gemstone strand, likely freshwater pearl or shell pearl
Pearl: nacreous calcium carbonate, chiefly aragonite (CaCO₃) in conchiolin; identification uncertain from image
Conglomerate
Conglomerate (clastic sedimentary rock)
Raw greenish crystal/mineral fragment
Uncertain from image; possibly olivine (forsterite-rich), epidote, or green tourmaline
Obsidian
Amorphous volcanic glass (primarily SiO2)
Fossiliferous Limestone with Brachiopod shell
Calcium carbonate (CaCO3)
Quartz-rich conglomeratic sandstone
Lithic arkose/conglomerate, dominated by quartz and feldspar grains
Chert (likely brown flint)
Microcrystalline quartz, SiO₂ (chalcedonic quartz aggregate)
Quartzite
Quartzite (primarily SiO2)
Piddock-bored Mudstone
Lutite (Siltstone or Mudstone) with Pholad borings
Fossilized Vertebra
Chordata fossil (Vertebra)
Amber
Succinite (C10H16O)
Snowflake Obsidian
Obsidian with Cristobalite inclusions (mostly amorphous SiO2)
Limestone
Calcareous sedimentary rock (CaCO3)
Chert (Jasper)
Silicon Dioxide (SiO2)
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Chert (and Jasper blend)
Chert (Microcrystalline Quartz, SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Chert / Flint
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Glauconitic Sandstone (Greensand pebble)
Glauconitic Quartz Sandstone (K(Fe,Al)2(Si,Al)4O10(OH)2)
Chert (and Limestone) River Cobble
Microcrystalline Quartz (SiO2) within Calcium Carbonate (CaCO3)
Chert (Jasper variety)
Chert (SiO2)
Chert (Black Chert/Flint)
Silicon Dioxide (SiO2)
Obsidian
Volcanic Glass (Amorphous SiO2)